Synthesis of 2H-benzotriazole based donor-acceptor polymers bearing carbazole derivative as pendant groups: Optical, electronical and photovoltaic properties

摘要

Four 2H-benzotriazole based D-A polymers bearing carbazole derivative as pendant groups andfluorene or thiophene as donor units (P1-P4) were designed and synthesized. These polymers combinegood thermal stability and excellent solubility in common organic solvents. Spectroscopicmeasurements carried out for P1, P2 and P3 indicate that polymer backbone induces effective thequenching of the 3,6-di(thiophen-2-yl)-9H-carbazole (CT) fluorescence, implying an intramolecularFrster Resonance Energy Transfer (FRET) process. Preliminary investigations on the photovoltaicmultiheterojunction devices based on P1-P4 showed power conversion efficiencies (PCEs) of up to 1.7% for P1 and P2 and close to 2.0 % for P3. This means that the polymer/-conjugated pendant unitsstructure is a promising alternative to improve the performance of organic solar cells.